When the session was at an end, Bristol was restored to a certain amount of favour, but during the troubled years which followed he took no part in politics, till the summons to the peers to take part in the expedition against the Scots in 1639 drew him from his seclusion. He pointed out the danger of advancing to Berwick with an undisciplined army. After the dissolution of the Short parliament in 1640 he urged the necessity of calling another parliament, and when the great council met at York in September he was practically accepted as its leader.
At the beginning of the Long parliament Bristol associated himself with those who wished to see a thorough change in the system of government, and on 19 Feb. 1641 he was summoned to a seat at the council board together with Bedford and five other reforming peers. He did his best to save Strafford's life, though he wished him to be incapacitated from office, and was consequently exposed to the insults of the mob. When the final vote was taken on the attainder bill, he was excused from voting on the ground that he had appeared in the trial as a witness. The course which he took gained him favour at court, and when the king set out for Scotland he named him gentleman of the bedchamber.
When parliament met again after the short autumn adjournment, the feeling between king and parliament had gone too far to be allayed by any statesmanship which Bristol possessed. We find him on 17 Dec. moving an amendment to a declaration against any toleration of the catholics, sent up by the commons, to the effect that no religion of any kind should be tolerated ‘but what is or shall be established by the laws of this kingdom.’ It is to be supposed that he was unwilling to see any considerable ecclesiastical change. At all events, on 27 Dec. he was named by the House of Commons as an evil counsellor. On the 28th Cromwell moved an address to the king to remove him from his counsels on the ground that in the preceding spring he had recommended that the northern army should be brought up against parliament. No evidence exists for or against this statement, but it is probable that Bristol suffered for the misdeeds of his mercurial son.
On 28 March 1642 Bristol was sent to the Tower on the ground that he had refrained from informing parliament of the Kentish petition, a copy of which had come into his hands. He was, however, liberated after a short confinement, and spoke twice in the House of Lords in favour of an accommodation. Finding his efforts fruitless, he shortly afterwards joined the king. He was with him at Oxford for some time after the battle of Edgehill, and was constantly spoken of by the parliamentary writers as being a warm advocate of the prolongation of the war. It is probable that his former connection with Spain did him harm, but too little is known of the working of parties at Oxford to pronounce on his conduct with any certainty. In January 1644 he advocated the policy of winning the support of the independents against the imposition of presbyterian uniformity (‘A Secret Negotiation with Charles I,’ Camden Miscellany, vol. vi.)
By the parliament Bristol was regarded with an abhorrence out of all proportion to any misdeeds of which evidence has reached us. In the propositions for peace presented at Oxford on 1 Feb. 1643, he and Lord Herbert of Raglan were named as the two persons to be removed from the king's counsels, to be restrained from coming within the verge of the court, and to be debarred from holding any office or employment (Rushworth, v. 166). In the propositions laid before the king in November 1644 as a basis for the negotiation to be held at Uxbridge, Bristol's name appears on a long list of those who were to expect no pardon (ib. 851). The increase of indignation perceptible in this demand is perhaps accounted for by the discovery of Bristol's part in the negotiation with the independents. He had, however, some time before these propositions were drawn up, removed from Oxford, in order to separate himself from those who were the advocates for the prolongation of the war. At first, he took refuge at Sherborne, but in the spring of 1644 he removed to Exeter, where he remained for about two years, till that city capitulated to Fairfax on 13 April 1646 (Lords' Journals, viii. 342). After the surrender of Exeter he petitioned to be allowed to compound for his estate by paying a composition, and to remain in England (ib. 343, 402); but his petition was rejected, and on 11 July the houses ordered a pass for him to go beyond the seas. The remainder of his life was passed in France. In 1647 he published at Caen a defence of his conduct in taking the king's part in the civil war under the title of ‘An Apology of John, Earl of Bristol.’ He died at Paris on 16 Jan. 1652–3 (Dugdale, Baronage).
